In this integrated investigation of environmental carcinogenesis, work will continue on the various related aspects of the study. In epidemiology, studies will continue on a number of cancer types, and include a recently initiated bias study on personal habits, a spouse study, a rare cancer study, and examination of contraceptive use in liver cancer. Nutritional aspects of breast cancer in humans and monkeys and in rats will continue to be studied from the point of view of fat-related hormonal changes, including investigations of basic mechanisms. Carcinogenicity of chemicals arising from the environment will be examined, and a new study started on bladder cancer, in which chemicals in human urine will be tested for mutagenic and carcinogenic activity in bacterial systems and mouse skins. Related animal model experiments will be carried out, including attempts to initiate prostate cancer in rats by direct injections of methylnitrosourea. BIBLIOGRAPHIC REFERENCES: Some reflections on the etiology of cancer of the breast. Wynder, E.L., Gantt, R.C. and Hill, P. In Cancer Detection and Prevention, Proc. 2nd Int'l. Symp. on Cancer Detection & Prevention, Bologna, April 9-12, 1973. (Maltoni, C., ed.) pp.197-204, 1974. Chan, P.C., Cohen, L.A. and Wynder, E.L. Prolactin and Estradiol Control Growth of Rat Mammary Adenocarcinoma Cells In Vitro. Proc. Am. Assoc. for Cancer Res. 16: 40, l975.